A clamshell mobile phone is disclosed in Japanese Patent Publication (Kokai), No. 2003-018267, which has two sections movably connected to each other, and may be used for voice communication no matter whether the two sections are open or closed to each other.
The above clamshell mobile phone has a mouthpiece 3, a first earpiece 4 and a second earpiece 5. The mouthpiece 3 and the first earpiece 4 may be used for voice communication while the two sections are being open (called an open mode). The mouthpiece 3 and the second earpiece 5 may be used for voice communication while the two sections are being closed (called a closed mode). In the closed mode, however, the first earpiece 4 for the open mode comes close to the mouthpiece 3, thereby may easily cause echoes.
So as to avoid the echoes by a mechanical means, the above clamshell mobile phone has a sound blocker 3b positioned, in the closed mode, between the mouthpiece 3 and the first earpiece 4 for the open mode. Besides, the clamshell mobile phone is configured, in the closed mode, so that a sound leaks from the first earpiece 4 in a direction “A” which is different from a direction “B” of the mouthpiece 3, as shown in FIG. 2 of the above Kokai reference.
So as to avoid the echoes by an electrical means, the above clamshell mobile phone may detect the mode, either open or closed. The clamshell mobile phone is configured to provide, in the open mode, only the first earpiece 4 for the open mode with sound signals. The clamshell mobile phone is configured to provide, in the closed mode, only the second earpiece 5 for the closed mode with sound signals.
The above clamshell mobile phone may hardly make echoes while being used for voice communication in the open mode, as the mouthpiece 3 and the first earpiece 4 are well separated in the open mode.
The above clamshell mobile phone may make echoes more easily while being used for voice communication in the closed mode than in the open mode, as separation between the mouthpiece 3 and the second earpiece 5 in the closed mode is not as large as separation between the mouthpiece 3 and the first earpiece 4 in the open mode. No attention seems to be paid in the above Kokai reference, however, to echoes possibly occurring between the mouthpiece 3 and the second earpiece 5 in the closed mode.